Mounting plate for ignition distributors and housing therefor



March 22, 1960 E. HAGMAIER ETAL 2,929,888

MOUNTING PLATE FOR mumou DISTRIBUTORS AND HOUSING THEREFOR Filed April29, 1958 2 Sheets-Sheet l March 22, 1960 E. HAGMAIER ETAL Filed April29, 1958 2 Sheets-Sheet 2 r 0 ii 4 Lli '2 #1 If i i v 5 la 73- MOUNTINGPLATE FOR IGNITION DISTRIBUTORS AND HOUSING THEREFOR Eugen Hagmaier,Stuttgart, Wilhelm Walther, Nussdorf- Sonnenherg, and Heinrich Bischotf,Korntal, Germany, assignors to Firma Robert Bosch G.m.b.H., Stuttgart,Germany Application April 29, 1958, Serial No. 731,840

Claims priority, application Germany May 11, 1957 13 Claims. (Cl.200-30) The present invention relates to distributors for batteryignition systems in internal combustion engines, and more particularlyto improved mounting plates and housing means for such apparatus.

ignition distributors of known construction comprise a housing receivinga mounting plate which supports the interrupter means, the purpose ofthe latter being to interrupt the primary current of the ignition unit.The assembly further comprises means for automatically varying theso--called sparking instant or ignition point.

Conventional mounting plates are formed with bent peripheral zonesprovided with tapped bores to receive a series of screws which passthrough the housing and secure the plate to the latter. The manufactureof such plates with tapped bores is rather costly and their mounting inthe housing a time consuming procedure. addition, if one or more screwsare drawn tighter than the others, tensions generated in the plate maycause slight or even considerable displacement or distortion thereofresulting in improper operation of the interrupter means mountedthereon, for example, by influencing the sparking instant due toimproper centering of said plate.

An object of the present invention is to provide a greatly simplifiedmounting plate for interrupters in internal combustion engines andsimplified housing therefor.

Another object of the invention is to provide a mounting plate of theabove described character which may be inserted into its housing in sucha way as to eliminate any and all tensions which would tend to displacethe plate from its desired position.

A further object of the invention is to provide an improved mountingplate and housing therefor which may be assembled without requiringinternal or external screw threads thereon.

An additional object of the invention is to provide a mounting plate forinterrupters in internal combustion engines and a housing therefor whichmay be locked against axial displacements with respect to each other bya single and removable element.

A concomitant object of the invention is to provide a housing formounting plates of the above described characteristics which may bepressed from a single piece of metallic material.

The above and other objects of the instant invention are attained by theprovision of a housing having a cylindrical bore and a plurality ofprojections therein which define spaced shoulders; of a mounting plateof generally discoidal contour insertable into the bore of the housingto rest on the shoulders of the projections therein; and of means forpreventing angular as well as axial displacements of the plate in saidhousing.

More particularly, the housing comprises an enlarged cylindrical portionand an axle journal for the timing shaft of the interrupter means. Theenlarged cylindrical portion is formed with a plurality of axiallyparallel ribs interrupted by an annular groove or recess. The lowerparts of so interrupted ribs serve as supports for the mounting plateand have their upper ends bounded by nited States Patent horizontalsurfaces against which selected peripheral portions of the lower surfaceof mounting plate abut. The lower end surfaces of the upper portions ofsaid ribs are preferably inclined so as to more firmly engage thelocking means which holds the mounting plate against axial displacementsin the housing.

The mounting plate is of discoidal contour and is provided withperipheral cutouts which allow its insertion along the upper parts ofribs to the level of the annular recess in cylindrical housing portion.The plate is then slightly turned and placed on the lower portions ofthe ribs in such position that one or more downwardly extending lips orprojections integral therewith abut against the adjacent ribs and thusprevent its angular displacements with respect to the housing.

The locking means against axial displacements of the plate preferablyconsists of a snap ring made of steel wire of circular cross sectionalcontour and at least partially received in the annular recess or groovein the cylindrical housing portion. In order to increase the lockingaction of the snap ring, selected peripheral portions of the mountingplate may he formed with outwardly and downwardly inclined uppersurfaces. In this manner, the snap ring is received between two inclinedsurfaces of preferably different inclinations which adds to the wedgingaction between the three parts as well as to safety against anyundesired displacements of the mounting plate which could lead toimproper ignition timing or other malfunctions of the interrupterassembly mounted thereon.

The housing with projections or ribs therein may be preferably made (bycasting, pressure casting, cold forming etc.) from any suitable metal oralloy, and the an nular recess or groove is machined therein, as byturning, in any convenient manner. Since the mounting plate and the snapring, too, are of extremely simple construction, the improved assemblyof these elements is considerably cheaper in manufacture and may beproperly assembled within an incomparably shorter time period thansimilar devices of known construction.

The novel features which are considered as characteristic for theinvention are at forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of a specificembodiment when read in connection with the accompanying drawings, inwhich:

Fig. 1 is a longitudinal section through the completely assembledignition distributor embodying our invention;

Fig. 2 is an axial section through the novel housing;

Fig. 3 is a top plan view of the novel mounting plate for theinterrupter assembly;

Fig. 4 is a central section through the mounting plate taken along linelVIV of Fig. 3; and

Fig. 5 is greatly enlarged detail view showing in section portions ofthe housing. of the mounting plate and of a snap ring for locking theplate in the housing.

Referring now in greater detail to the illustrated embodiment, Fig. 1shows an assembled ignition distributor comprising a housing consistingof a cylindrical portion 1i) and a tubular extension or axle journal 11,the latter receiving a distributor or timing shaft 12. Housing 10, 11may be made by cold forming from a single cylindrical piece of aluminumtogether with spaced ribs 13 disposed in the bore of cylindrical portion10. An annular groove 14, best shown in Fig. 2, is machined into theinner wall of housing portion 10 and thus interrupts each of the ribs 13adjacent to the upper ends of the latter. A shoulder or platform 15 isformed at the upper end of the lower portion of each rib 13 beneath thegroove 14, these shoulders supporting a mounting plate 16, shown ingreater detail in Figs. 3

Pafented Mar. 22, 1960 and 4, which in turn'rnounts a swingable plate17. Plate 17 supports an interrupter for the primary current of anignition coil (not shown). Mounting plate 16 is held against axialdisplacements in housing portion it by a snap ring 18 which is wedgedinto the space between the inclined surfaces 13 of the ribs 13 andperipheral portions 16 f plate 16, respectively.

The interrupter is controlled by a cam 20 which is mounted on timingshaft 12 and is swingable under the influence of a flyweight governor 19in dependency on rotational speed of the engine. Plate 17, whose purposeis to support the distributor assembly, has an annular extension orcollar 17 rotatably received in the circular opening 16 of mountingplate 16. A vacuum shifter or regulator is fixed externally to thecylindrical housing portion it); it comprises a diaphragm casing 21 andan actuating member 17'. One end of member 17" is connected to thediaphragm (not shown) in casing 21 while its other end engages theswingable plate 17. Any movements imparted by the diaphragm to member17" are conveyed to plate 17 which swings in its own plane and causesdisplacements of the interrupter assembly mounted thereon. The sodisplaced interrupter causes corresponding changes in the sparkinginstant.

The upper end of timing shaft 12 supports a traveler 22 carrying anelectrode 23 which latter, during its travel about shaft 12, makescontact with and conveys high voltage impulses to distributor electrodes24, mounted in plateau 25, and thence to the spark plugs (not shown) ofthe internal combustion engine with which the just described distributorassembly is associated.

It will be noted in Figs. 3 and 4 that the main body of plate 16, aswell as its peripheral zones 16, save for small downwardly bent lips 26,extend in a single plane. The novel mounting plate thus overcomes theabove mentioned disadvantages of known constructions caused by unevendistribution of tensions therein and by more complicated and lengthierassembly with the housing. The mounting plate may be introduced throughthe open end of housing portion 19 down to the level of shoulders 15 andis then retained in such position by snap ring 13. Housing 16, ill isbest shown in Fig. 2. It will be noted here that the annular groove 14extends into thematerial of housing part ft) and is limited therein by alower horizontal surface 14:: as well as by an upper inclined surface14b continuing into surfaces 13 on parts of ribs 13 above the groove 14.The inclination of surfaces 14b and 13' is approximately 45 degrees.Shoulders 15 are preferably somewhat below the level of surface 14a, asis best shown in Fig. 5. Mounuting plate 16, shown in detail in Figs. 3and 4, has a seri s of peripheral cutouts 25 for the passage of upperportions of ribs 13 when the plate is inserted into the open end ofhousing part 10 and caused to descend in downward direction. Uponreaching the level of annular groove 14, plate 16 is turned through asmall angle in a horizontal plane and thereupon placed onto theshoulders 2.5 in such position that the two downwardly extending lips orprojections 25 abut against a pair of adjacent ribs 13. Theseprojections 26 thus positively prevent rotation of the plate. As will benoted in Figs. 4 and 5, peripheral zones to of plate 16 between cutouts25 are formed with downwardly and outwardly inclined upper surfaces 27against which the snap ring 18 abuts.

The section of Fig. is taken through a longitudinal rib 13. Thisillustration shows that the plate is is supported merely by shoulders15, and further shows a projection 26 in abutting relationship with theradial surface of rib 13.

a Snap ring 18 is made of steel wire. The inclination of surface 27 onplate 16 is about 25 degrees and that of surfaces 14:), 13' about 45degrees. Such different inclinations of Surfaces in contact with thesnap ring 18 causethe latter to be wedged in firm contact with thehousing part If? and ribs 13 on the one hand, and with the mountingplate 16 on the other hand. Member 18 thus maintains the plate indesired central position in the bore of housing part 10 in addition topreventing axial displacements between parts It and 16.

it will be noted in Fig. 5 that the distance between surfaces 13' andshoulders 15 is sufficient to permit angular displacements of plate 16in a position in which the lips 26 are still above the levels of saidshoulders; This allows for so rotating the plate that its lips 2-6engage a pair of ribs 13 from opposing sides and thus positively preventany angular displacements of the plate when the latter rests upon theshoulders 15. In addition, the location of grbove 14 with respect toplate 16, when the latter is seated on shoulders 15, is so selected thatthe snap ring extends into said groove and bears against the inclinedperipheral surface 141; in housing portion 19.

it will be understood that one or theother of elements 7 described abovemay also find a useful application'in other types of distributorsdiffering from the type described hereinabove.

Without further analysis, the foregoing will so'fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for vari ous applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as and desired to be secured by Letters Patent is:

1. In an ignition device for internal combustion engines havinginterrupter means, in combination, housing means, having an axial boreof cylindrical contour; a plurality of axially parallel ribs in saidbore integral with said housing means; said housing means having anannular recess in said bore interrupting each of said ribs and each ofsaid ribs having a first surface and a second surface inclined withrespect to said first surface with said recess disposed between'saidfirst and said second surfaces, said first surfaces of said ribs beingin a common plane at right angles to the axis of said bore; a mountingplate for said interrupter means, said plate being of discoidal contour,of a diameter approximating that of said bore, and having a first majorsurface, a second major surface, a peripheral zone bounded at one sideby said first major surface and at the other side by a surfacecontiguous to said second major surface and inclined with respect tosaid first major surface, a plurality of cutouts in said peripheral zoneso spaced as to receive and permit passage of said ribs therethroughwhen said plate is inserted into the bore of said housing means, and atleast two lips extending from the general plane of said plate to theside of said first major surface, said plate being inserted into thebore of said housing means in such a way that selected portions of theperipheral zone thereof at the side of said first major surface restupon the first surfaces of said ribs and each of said lips engages oneof said ribs for holding the plate against angular displacements in saidbore; and a snap ring extending into the recess in said housing meansand engaging with the second surfaces of said ribs and the I inclinedsurface of said peripheral zone for holding said plate against axialdisplacements in said bore.

2. In an ignition device for internal combustion engines, in'combination, housing means having an axial bore of cylindrical contour;a plurality of axially parallel ribs in said bore integral with saidhousing means; said housing means having an annular recess in said boreinterrupting each of said ribs; each of said ribs having a first surfaceand a second surface inclined with respect to said first surface, saidrecess extending between the first and the second surfaces of said ribs,said first surfaces of said ribs being in, a common plane substantially'5 at right angles to the axis of said bore and saidsecond surfacesbeing inclined through approximately 45 degrees with respect to saidfirst surfaces; a mounting plate for said interrupter means, said platebeing of discoidal contour, of a diameter approximating that of saidbore, and having a first major surface, a second major surface, aperipheral zone bounded at one side by said first major surface and atthe other side by a surface contiguous with said second major surfaceand inclined through about degrees with respect to said first majorsurface, a plurality of cutouts in said peripheral zone so spaced as toreceive and permit passage of said ribs therethrough when said plate isinserted into the bore of said housing means, and at least two lipsextending from the general plane of said plate to the side of said firstmajor surface, said plate being inserted into the bore of said housingmeans in such a way that selected portions of the peripheral zone at theside of said first major surface rest upon the first surfaces of saidribs and each of said lips engages one of said ribs for holding theplate against angular displacements in said bore; and a snap ringpartially extending into the recess in said housingmeans, said ringfurther engaging with the second surfaces of said ribs and the inclinedsurface of said peripheral zone for holding the plate against axialdisplacements in said bore.

3. In an ignition device for internal combustion en gines, incombination, housing means having an end and an axial bore'extendinginwardly from said end; a plurality of axially parallel ribs in saidbore integral with said housing means; said housing means having anannular recess in said bore dividing each of said ribs into a firstportion and a second portion, the first portion of each of said ribshaving an end surface with said end surfaces disposed in a common planeat right angles to the axis of said bore, and the second portion of eachof said ribs having an end surface incl ned with respect to the endsurface of said first portion, said recess extending between the endsurfaces of the first and second portions of said ribs; a mounting platefor said interrupter means, said plate being of discoidal contour, of adiameter approximating the diameter of said bore, and having a firstmajor surface, a second major surface, a peripheral zone bounded at oneside by said first major surface and at the other side by a surfacecontiguous with said second major surface and inclined with respect tosaid first major surface, a plurality of cutouts in said peripheral zoneso spaced as to receive and permit passage of the second portions ofsaid ribs therethrough when said plate is inserted into the bore of saidhousing'means, and at least two lips extending from the general planeofsaicl plate to the side of said first major surface, said plate beinginserted into the bore from the end of said housing means in such a Waythat selected portions of'the peripheral zone at the side of said firstmajor surface rest upon the end surfaces of the first portions of saidribs and each of said lips engages one of the first portions of saidribs for holding the plate against angular displacemerits in said bore;and a snap ring partially extending into the recess in said housingmeans, said ring further engaging with the end surfaces of the secondportions of said ribs and with the inclined surface of said peripheralzone for holding the plate against axial displacements in said bore, theinclinations of the end surfaces of the second portions of said ribsbeing different from the inclination of said inclined surface of theperipheral zone of said plate when the latter is retained by said snapring in said bore.

4. In an ignition device for internalcornbustion engines, incombination, aluminum housing means having an end and an axial boreextending inwardly from said end; a plurality of axially parallel ribsin said bore inte gral with said housing means; said housing meanshaving an annular recess in said bore dividing each of said ribs into afirst portion and a second portion, the first portion ofeach of saidribs having an end surface with said end surfaces disposed in a commonplane at right angles to the axis of said bore, and the second portionof each of said ribs having an end surface inclined with respect to theend surface of said first portion, said recess extending between the endsurfaces of the first and second portions of said ribs; a mounting platefor said interrupter means,

said plate being of discoidal contour, of a diameter approximating thediameter of said bore, and having a first major surface, a second majorsurface, a peripheral zone bounded at one side by said first majorsurface and at the other side by a surface contiguous with said secondmajor surface and inclined with respect to said first major surface, aplurality of cutouts in said peripheral zone so spaced as to receive andpermit passage of the second portions of said ribs therethrough whensaid plate is inserted into the bore of said housing means, and at leasttwo lips extending from the general plane of said plate to the side ofsaid first major surface, said plate being inserted into the bore fromthe end of said housing means in such a way that selected portions ofthe peripheral zone at the side of said first major surface rest uponthe end surfaces of the first portions of said ribs and each of saidlips engages one of the first portions of said ribs for holding theplate against angular displacements in said bore; and a snap ringpartially extending into the recess in said housing means, said ringfurther engaging with the end surfaces of the second portions of saidribs and with the inclined surface of said peripheral zone for holdingthe plate against axial displacements in said bore, the inclinations ofthe end surfaces of the second portions of said ribs being differentfrom the inclination of said inclined surface of the peripheral zone ofsaid plate when the latter is retained by said snap ring in said bore.

5. In an ignition device for internal combustion engines havinginterruptor means, in combination, housing means having an axial bore; aplurality of axially parallel ribs in said bore integral with saidhousing means, said housing means having an annular recess in said boreinterrupting each of said ribs and each of said ribs having a firstsurface and a second surface, said surfaces extending in a radialdirection, with said recesses disposed between said first and secondsurfaces; a mounting plate for said interruptor means, said plate beingof discoidal contour and of a size approximating the cross section ofthe bore, and having a peripheral zone formed with a plurality ofcutouts so spaced as to receive and permit passage of said ribstherethrough when said plate is inserted into the bore of said housingmeans, and at least two lips axially extending from the general plane ofsaid plate, said plate being inserted into the bore of said housingmeans in such a manner that selected portions of the peripheral zonethereof rest upon the first surfaces of said ribs and each of said lipsengages one of said ribs for holding the plate against angulardisplacement in said bore, said second surfaces of said ribs facingopposite portions of said peripheral zone and being inclined withrespect to said opposite portions so as to define therewith radiallyextending recesses tapering in a radially outward direction; and snapring means in said radially tapering recesses engaging said secondsurfaces and said opposite portions for holding said plate against axialdisplacement in said bore.

6. In an ignition device for internal combustion engines havinginterruptor means, in combination, housing means having an axial bore ofcylindrical contour; a plurality of axially parallel ribs in said boreintegral with said housing means, said housing means having an annularrecess in said bore interrupting each of said ribs and each of said ribshaving a first surface and a second surface, said surfaces extending ina radial direction, with said recess disposed between said first andsecond surfaces; a mounting plate for said interruptor means, said platebeing of discoidal contour and of a size approximating the cross sectionof said bore, and having a peripheral zone formed with a plurality ofcutouts so spaced as to receive and permit passage of said ribstherethrough when said plate is inserted into the bore of said housingmeans, and at least two lips axially extending from the general plane ofsaid plate, said plate being inserted into the bore of said housingmeans in such a manner that selected portions of the peripheral zonethereof rest upon the first surfaces of said ribs and each of said lipsengages one of said ribs for holding the plate against angulardisplacement in said bore, said second surfaces of said ribs facingopposite portions of said peripheral zone and being inclined withrespect to said opposite portions so as to define therewith radiallyextending recesses tapering in a radially outward direction; and snapring means in said radially tapering recesses engaging said secondsurfaces and said opposite portions for holding said plate against axialdisplacement in said bore.

7. In an ignition device for internal combustion engines havinginterrupter means, in combination, housing means having an axial bore; aplurality of axially parallel ribs in said bore integral with saidhousing means, said housing means having an annular recess in said boreinterrupting each of said ribs and each of said ribs having a firstsurface and a second surface, said surfaces extending in a radialdirection, with said recess disposed between said first and secondsurfaces, said first surfaces of said ribs being in a common plane atright angles to the axis of the bore; a mounting plate for saidinterrupter means, said plate being of discoidal contour and of a sizeapproximating the cross section of said bore, and having a peripheralzone formed with a plurality of cutouts so spaced as to receive andpermit passage of said ribs therethrough when said plate is insertedinto the bore of said housing means in such a manner that selectedportions of the peripheral zone thereof rest upon the first surfaces ofsaid ribs and each of said lips engages one of said ribs for holding theplate against angular displacement in said bore, said second surfaces ofsaid ribs facing opposite portions of said peripheral zone and beinginclined with respect to said opposite portions so as to definetherewith radially extending recesses tapering in a radially outwarddirection; and snap ring means in said radially tapering recessesengaging said second surfaces and said opposite portions for holdingsaid plate against axial displacement in said bore.

8. in an ignition device for internal combustion engines havinginterruptor means, in combination, housing means having an axial bore; aplurality of axially parallel ribs in said bore integral with saidhousing means, said housing means having an annular recess in said boreinterrupting each of said ribs and each of said ribs having a firstsurface and a second surface, said surfaces extending in a radialdirection, with said recessdisposed between said first and secondsurfaces; a mounting plate for said interrupter means, said plate beingof discoidal contour and of a size approximating the cross section ofsaid bore, said plate having a first major surface, a second majorsurface, a peripheral zone, bounded at one side by said first majorsurface and at the other side by a surface contiguous to said secondmajor surface, and formed with a plurality of cutouts so spaced as toreceive and permit passage of said ribs therethroughwhen said plate isinserted into the bore of said housing means, and at least two lipsaxially extending from the general plane of said plate, said plate beinginserted into the bore of said housing means in such a manner thatselected portions of the peripheral zone thereof rest upon the firstsurfaces of said ribs and each of said lips engages one of said ribs forholding the plate against angular displacement said bore, said secondsurfaces of said ribs facing opposite portions of said peripheral zoneand being inclined with respect to said opposite portions so as todefine therewith radially extending recesses tapering in a radiallyoutward direction; and snap ring means in said radially taperingrecesses engaging said second surfaces and said opposite portions forholding said plate against axial displacement in said bore.

9. In an ignition device for internal combustion engines havinginterruptor means, in combination, housing means having an axial bore; aplurality of axially parallel ribs in said bore integral with saidhousing means, said housing means having an annular recess in said boreinterrupting each of said ribs and each of said ribs having a firstsurface and a second surface, said surfaces extending in radialdirection, with said recess disposed between said first and secondsurfaces; a mounting plate for said interruptor means, said plate beingof discoidal contour and of a size approximating the cross section ofsaid bore, said plate having a first major surface, a second majorsurface, a peripheral zone, bounded at one side by said first majorsurface and at the other side by a surface contiguous to said secondmajor surface and inclined with respect to said first surface, andformed with a plurality of cutouts so spaced as to receive and permitpassage of said ribs therethrough when said plate is inserted into thebore of said housing means, and at least two lips axially extending fromthe general plane of said plate, said plate being inserted into the boreof said housing means in such a manner that selected portions of theperipheral zone thereof rest upon the first surfaces of said ribs andeach of said lips engages one of said ribs for holding the plate againstangular displacement in said bore, said second surfaces of said ribsfacing opposite portions of said peripheral zone and being inclined withrespect to said opposite portions so as to define therewith radiallyextending recesses tapering ina radially outward direction; and snapring means in said radially tapering recesses engaging said secondsurfaces and said opposite portions for holding said plate against axialdisplacement in said bore.

10. In an ignition device for internal combustion engines havinginterruptor means, in combination, housing means having an axial bore; aplurality of axially parallel ribs in said bore integral with saidhousing means, said housing means having an annular recess in said boreinterrupting each of said ribs and each of said ribs having a firstsurface and a second surface, said surfaces extending in a radialdirection, with said recess disposed between said first and secondsurfaces; a mounting plate for said interruptor means, said plate beingof discoidal contour and of a size approximating the cross section ofsaid bore, said plate having a first major surface, a second majorsurface, a peripheral zone, bounded at one side by said first majorsurface and at the other side by a surface contiguous to said secondmajor surface, and formed with a plurality of cutouts so spaced as toreceive and permit passage of said ribs therethrough when said plate isinserted into the bore of said housing means, and at least two lipsaxially extending from the general plane of said plate to the side ofsaid first major surface, said plate being inserted into the bore ofsaid housing means in such a manner that selected portions of theperipheral zone thereof rest upon the first surfaces of said ribs andeach of said lips engages one of said ribs for holding the plate againstangular displacement in said bore, said second surfaces of said ribsfacing opposite portions of said peripheral zone and being inclined withrespect to said opposite portions so as to define therewith radiallyextending recesses tapering in a radially outward direction; and snapring means in said radially tapering recesses engaging said secondsurfaces and said opposite portions for holding said plate against axialdisplacement in said bore.

11. In an ignition device for internal combustion engines havinginterrupter means, in combination, housing means having an axial bore; aplurality of axially parallel ribs in said bore integral with saidhousing means, said housing means having an annular recess in said boreinterrupting each of said ribs and each of said ribs having a firstsurface and a second surface, said surfaces extending in a radialdirection, with said recess disposed between said first and secondsurfaces; a mounting plate for said interruptor means, said plate beingof discoidal contour and of a size approximating the cross section ofsaid bore, said plate having a first major surface, a second majorsurface, a peripheral zone, bounded at one side by said first majorsurface and at the other side by a surface contiguous to said secondmajor surface, and formed with a plurality of cutouts so spaced as toreceive and permit passage of said ribs therethrough when said plate isinserted into the bore of said housing means, and at least two lipsaxially extending from the general plane of said plate, said plate beinginserted into the bore of said housing means in such a manner thatselected portions of the peripheral zone thereof at the side of saidfirst major surface rest upon the first surfaces of said ribs and eachof said lips engages one of said ribs for holding the plate againstangular displacement in said bore, said second surfaces of said ribsfacing opposite portions of said peripheral zone and being inclined withrespect to said opposite portions so as to define therewith radiallyextending recesses tapering in a radially outward direction; and snapring means in said radially tapering recesses engaging said secondsurfaces and said opposite portions for holding said plate against axialdisplacement in said bore.

12. In an ignition device for internal combustion engines havinginterruptor means, in combination, housing means having an axial bore,said housing means consisting of a single piece of press-formed metal; aplurality of axially parallel ribs in said bore integral with saidhousing means, said housing means having an annular recess in said boreinterrupting each of said ribs and each of said ribs having a firstsurface and a second surface, said surfaces extending in a radialdirection, with said recess disposed between said first and secondsurfaces; a mounting plate for said interruptor means, said plate beingof discoidal contour and of a size approximating the cross section ofsaid bore, and having a peripheral zone formed with a plurality ofcutouts so spaced as to receive and permit passage of said ribstherethrough whensaid plate is inserted into the bore of said housingmeans, and at least two lips axially extending from the general plane ofsaid plate, said plate being inserted into the bore of said housingmeans in such a manner that selected portions of the peripheral zonethereof rest upon the first surfaces of said ribs and each of said lipsengages one of said ribs for holding the plate against angulardisplacement in said bore, said second surfaces of said ribs facingopposite portions of said peripheral zone and being inclined withrespect to said opposite portions so as to define therewith radiallyextending recesses tapering in a radially outward direction; and snapring means in said radially tapering recesses engaging said secondsurfaces and said opposite portions for holding said plate against axialdisplacement in said bore.

13.In an ignition device for internal combustion engines havinginterruptor means, in combination, housing means having an axial bore,said housing means consisting of a single piece of press-formedaluminum; a plurality of axially parallel ribs in said bore integralwith said housing means, said housing means having an annular recess insaid bore interrupting each of said ribs and each of said ribs having afirst surface and a second surface, said surfaces extending in a radialdirection, with said recess disposed between said first and secondsurfaces; a mounting plate for said interruptor means, said plate beingof discoidal contour and of a size approximating the cross section ofsaid bore, and having a peripheral zone formed with a plurality ofcutouts so spaced as to receive and permit passage of said ribstherethrough when said plate is inserted into the bore of said housingmeans, and at least two lips axially extending from the general plane ofsaid plate, said plate being inserted into the bore of said housing insuch a manner that selected portions of the peripheral zone thereof restupon the first surfaces of said ribs and each of said lips engages oneof said ribs for holding the plate against angular displacement in saidbore, said second surfaces of said ribs facing opposite portions of saidperipheral zone and being inclined with respect to said oppositeportions so as to define therewith radially extending recesses taperingin a radially outward direction; and snap ring means in said radiallytapering recesses engaging said second surfaces and said oppositeportions for holding said plate against axial displace ment in saidbore.

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